Process of acetylizing cellulose



the mono-ch Patented ug. 28, 1923.

httdttt HARRY P. sassnrr, OF CYNTEIANA, KENTUCKY.

PROCESS 0F ACETYLIZING CELLULOSE.

Kc Drawing.

To all; whom it may covwem Be it known that I, HARRY P. BAssE'rr, acitizen of the United States, residing at Cynthiana, in the county ofHarrison and State of Kentucky, have invented certain new andusefulImprovements in Processes of Aoetylizing Cellulose, of which thefollowing is a specification.

This invention relates to processes of acetylizing cellulose and similarsubstances.

An. object of the present invention is to recover the acetylizingmaterial for reuse in the process.

A. further object is to employ sulfur chlorid and dry chlorine gas totreat therecovered acetg lizing material and to recover or-acetic acidformed.

In practicing the process, suitable cellulose material such as bleachedcotton linters is first treated with acetic anhydride con-= vtainingsulfuric acid 'o'r other mineral acid or acid salt. A smallamount, of benaol,

toluol, or other coal tar product is added to the mixture and themixture allowed to stand for a sufiicient'length of time to acety- Iizethe ellulose- The excess ecetylizing mixture is removed-from thecellulose ace= tate formed and the cellulose acetate Washed,

dried,'and treated inany other manner for purifying.

The recovered acetylizing mixture is then distilled to recover thebenzol, toluol, or

similar material employed. Sulfur chlorid is then added to the residue,and the residue treated with dry chorine, forming acetyl chlorid and asmall amount of mono-chloracetic acid. The .mono-chlor-aoetic acid is searated and recovered for use in the erts. e amtyl chlorid isthen-treated with anhydrous sodium acetate and distilled, forming aceticanhydride which, may he em.- ploycd in practicing the process.

In a typical embodiment of the invention, the acetylizing mixture ispreparedin substentially the proportions'of' 366 parts of per centacetic enhydride ('20 per cent acetic acid}, 1200 parts of henzol,.and10 parts of 5 per cent Sulfuric acid. As stated, other acid may beemployedin. lsce of sulfuric acid,.such as benzene su onic acid,phosphoric acid, vand other mineral-acids and. acid salts. In. place ofbenzol, .toluol, and other coal tar products may-be employed. Thecellulose to he treated, preferably in n purified oonditiomsuch asbleached cotton linters is then added to the mixture, the

Application filed may 1.1, 1921. Serial Ito. 4%,695.

acetylizing mixture being employed in excess of the theoreticalrequirements.

This mixture is allowed to stand until tests show that the cellulose hasbeen completely acctylized, or acetylized to the desired degree. I havefound that in actual practice, a period of about 18 hours is generallysuficient for acetylizing. The cellulose acetate formed is separated inany suit able manner from the excess ecetylizing mixture. The use of acentrifugel machine for separating the cellulose acetate is advantageous. Upon separation, the cellulose acetate is washed, dried, and treatedin any other mnnner. desired for placing it in con.- dition for themarket. J 7

, The recovered acetylizing mixture is first distilled to remver thetoluol,.or other dilueat. The residue is then treated with sulfurchlorid and'dry chlorine gas is lead into the .mixture for sufiicientlength of time to per chlorine treetment, a nnall amount ofmonochlor-acetic acid is formed which is separated from the acetylchlorid formed and recovered for use in the arts The acetyl chlorid isthen treated with so dium. acetate and distilled to form aceticanhydride.

While l hevedescrihed in detail the pre ferredprlactice ofmy process, itis to M understood thet the details of procedure, and

proportion of ingredients m be widely varied, and that known chemicalequivalents may be employed in place of the mawria-ls mentioned, withoutdeperting from the.

spiritfo'f the invention or the scope'of the subjoined claims. 7

Havingf thus described my invention, I

- claim 1. hprocws of the character descri l which comprises treatingcellulose with an acetylizing mixture containing suhstentially 300perisof 80 per cent acetic'anhydride,

1200 of a coal tar product, and 10 parts of sulfuric acid, separatingcellulose acetate, removing the coal tar product "item the mixture bydistillation, and trusting said mixture to recover acetic anhydride.

2. A. process of the character descrihed not which comprises treatingcellulose with an acetylizing mixture containing suhstentially 300 pertsof 80 per cent acetic anhydride, 1200 parts of benzol, and 10 parts ofsulfuric acid, separating cellulose *acetate, re

movi the bemzol from the mixture by distilleiion, end treetin saidmixture mow-recovei" acetic enhydri e.

3. A prooess of he charm-57erdescribed which comprises treatingcellulose with an ecetyliziiig mixem-e oonteining subemntielly 3% partsof 80 per eent acetic enhydride, 1200 eres of a. eoel tee product, end10 parts of sulfuric acid, separeti cellulose acetate, mmoving the coaltea product from fine mixture by distillation, adding sulfur chloride tothe remaining materiel, and

Meeting said materiel with chlorine gas to form eeetyl chloride.

em process of the character described "which comprises meeting cellulosewith m eeetylizimg mixtme containing suleslentielly 300 parts of 80 percent ecetie enliydride, 1200 pear-ts of e coal mi" proolme, and. 10parts of sulfuric ecid,'sepm'ating cellulose eeetete, removing the coalter product from the mixem'e by olistilleeion, adding sulfur ehloridetothe remaining materiel, treating seid meeeriel with. chlorine gas toform eeetyl chloride; end -treeting the acetyl CMQIld' with sodiumacetate to form. acetic enhydride.

lln eesfiaimon whereof I affix my signature in presence 0 two witnesws.

Fmommoe M.- 0.

